The mkcksum() function now takes one parameter, the pointer to 11-byte wide character array, which it then operates on.
Currently, the function is wrongly passed (dir_entry)->name, which is only 8-byte wide character array. Though by further inspecting the dir_entry structure, it can be noticed that the name[8] entry is immediatelly followed by ext[3] entry. Thus, name[8] and ext[3] in the dir_entry structure actually work as this 11-byte wide array since they're placed right next to each other by current compiler behavior.
Depending on this is obviously wrong, thus fix this by correctly passing both (dir_entry)->name and (dir_entry)->ext to the mkcksum() function and adjust the function appropriately.
Signed-off-by: Marek Vasut marex@denx.de Cc: Tom Rini trini@ti.com --- fs/fat/fat.c | 20 ++++++++++++-------- fs/fat/fat_write.c | 2 +- 2 files changed, 13 insertions(+), 9 deletions(-)
V2: Fix fat write by adding braces
diff --git a/fs/fat/fat.c b/fs/fat/fat.c index 41ae15e..8870292 100644 --- a/fs/fat/fat.c +++ b/fs/fat/fat.c @@ -567,15 +567,16 @@ get_vfatname(fsdata *mydata, int curclust, __u8 *cluster, }
/* Calculate short name checksum */ -static __u8 mkcksum(const char *str) +static __u8 mkcksum(const char name[8], const char ext[3]) { int i;
__u8 ret = 0;
- for (i = 0; i < 11; i++) { - ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + str[i]; - } + for (i = 0; i < sizeof(name); i++) + ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + name[i]; + for (i = 0; i < sizeof(ext); i++) + ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + ext[i];
return ret; } @@ -678,7 +679,8 @@ static dir_entry *get_dentfromdir(fsdata *mydata, int startsect, return NULL; } #ifdef CONFIG_SUPPORT_VFAT - if (dols && mkcksum(dentptr->name) == prevcksum) { + __u8 csum = mkcksum(dentptr->name, dentptr->ext); + if (dols && csum == prevcksum) { prevcksum = 0xffff; dentptr++; continue; @@ -946,13 +948,16 @@ do_fat_read_at(const char *filename, unsigned long pos, void *buffer,
for (i = 0; i < DIRENTSPERBLOCK; i++) { char s_name[14], l_name[VFAT_MAXLEN_BYTES]; + __u8 csum;
l_name[0] = '\0'; if (dentptr->name[0] == DELETED_FLAG) { dentptr++; continue; } - if ((dentptr->attr & ATTR_VOLUME)) { + + csum = mkcksum(dentptr->name, dentptr->ext); + if (dentptr->attr & ATTR_VOLUME) { #ifdef CONFIG_SUPPORT_VFAT if ((dentptr->attr & ATTR_VFAT) == ATTR_VFAT && (dentptr->name[0] & LAST_LONG_ENTRY_MASK)) { @@ -1015,8 +1020,7 @@ do_fat_read_at(const char *filename, unsigned long pos, void *buffer, goto exit; } #ifdef CONFIG_SUPPORT_VFAT - else if (dols == LS_ROOT && - mkcksum(dentptr->name) == prevcksum) { + else if (dols == LS_ROOT && csum == prevcksum) { prevcksum = 0xffff; dentptr++; continue; diff --git a/fs/fat/fat_write.c b/fs/fat/fat_write.c index 5829adf..4a1bda0 100644 --- a/fs/fat/fat_write.c +++ b/fs/fat/fat_write.c @@ -335,7 +335,7 @@ fill_dir_slot(fsdata *mydata, dir_entry **dentptr, const char *l_name)
/* Get short file name and checksum value */ strncpy(s_name, (*dentptr)->name, 16); - checksum = mkcksum(s_name); + checksum = mkcksum((*dentptr)->name, (*dentptr)->ext);
do { memset(slotptr, 0x00, sizeof(dir_slot));